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                <h2 id="React-的学习"><a href="#React-的学习" class="headerlink" title="React 的学习"></a>React 的学习</h2><blockquote>
<p>react 有一个组件库 <a href="https://ant.design/" target="_blank" rel="noopener">https://ant.design/</a></p>
</blockquote>
<p>引入组件库 UI</p>
<pre><code>npm install -D antd
// 按需引入
npm install -D babel-plugin-import</code></pre><p>修改配置文件 .babelrc</p>
<pre><code>// .babelrc or babel-loader option
{
  "plugins": [
    ["import", { "libraryName": "antd", "libraryDirectory": "es", "style": "css" }] // `style: true` 会加载 less 文件
  ]
}</code></pre><h3 id="1-React-项目创建"><a href="#1-React-项目创建" class="headerlink" title="1. React 项目创建"></a>1. React 项目创建</h3><pre class=" language-shell"><code class="language-shell">npm install -g create-react-app
//创建 项目
create-react-app 项目名</code></pre>
<h3 id="2-React-元素的渲染"><a href="#2-React-元素的渲染" class="headerlink" title="2. React 元素的渲染"></a>2. React 元素的渲染</h3><pre><code>
class ShoppingList extends React.Component {
  render() {
    return (
      &lt;div className="shopping-list"&gt;
        &lt;h1&gt;Shopping List for {this.props.name}&lt;/h1&gt;
        &lt;ul&gt;
          &lt;li&gt;Instagram&lt;/li&gt;
          &lt;li&gt;WhatsApp&lt;/li&gt;
          &lt;li&gt;Oculus&lt;/li&gt;
        &lt;/ul&gt;
      &lt;/div&gt;
    );
  }
}

// 用法示例: &lt;ShoppingList name="Mark" /&gt;</code></pre><p>JSX 语法</p>
<pre><code>let h1 = &lt;h1&gt; hello word &lt;/h1&gt;;
// 但是 只能有一个根节点
let root = document.querySelecter('#root');
ReactDOM.render(h1,root);// (渲染的组件，渲染到某个节点上)</code></pre><p><code>实例1:浏览器中实现一个时间</code></p>
<ul>
<li>方式1</li>
</ul>
<pre><code>function clock(){
    let time = new Date().toLocaleTimeString();
    let element = &lt;h1&gt; 现在时间是 {time} &lt;/h1&gt;;
    let root = document.querySelecter('#root');
    ReactDOM.render(element,root);// (渲染的组件，渲染到某个节点上)
}

clock();

// 间隔函数
setInterval(clock,1000);</code></pre><ul>
<li>方式2</li>
</ul>
<pre><code>// react 函数式组件
function Clock(props){
    return {
        &lt;div&gt;
            &lt;h1&gt; 现在时间是 {props.date.toLocaleTimeString()} &lt;/h1&gt;
        &lt;/div&gt;
    }    
}
function run (){
    ReactDOM.render(
        &lt;Clock date={new Date()} /&gt;,
        document.querySelecter('#root')
    );
}

setInterval(run,1000);

run();</code></pre><h3 id="3-React-JSX-语言"><a href="#3-React-JSX-语言" class="headerlink" title="3. React-JSX 语言"></a>3. React-JSX 语言</h3><p>优点：</p>
<ul>
<li>JSX 执行更快，编译为 JavaScript 代码时进行了优化</li>
<li>类型更安全，编译过程如果出错就不能编译</li>
<li>JSX 编写模板更加简单快速（不要和 VUE 比较）</li>
</ul>
<p>注意：</p>
<ol>
<li>JSX 必须由根节点</li>
<li>正常的普通 HTML 元素要小写，如果大写，会被默认为组件</li>
</ol>
<h3 id="4-React-组件"><a href="#4-React-组件" class="headerlink" title="4. React 组件"></a>4. React 组件</h3><blockquote>
<p>一个大的组件 是可以 嵌套 组件的。</p>
</blockquote>
<ul>
<li><code>函数式组件</code></li>
</ul>
<p><code>注意：</code> 函数式组件 一定要大写 ！！！！</p>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">function</span> <span class="token function">Clock</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token punctuation">{</span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span> 现在时间是 <span class="token punctuation">{</span>props<span class="token punctuation">.</span>date<span class="token punctuation">.</span><span class="token function">toLocaleTimeString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">}</span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
    <span class="token punctuation">}</span>    
<span class="token punctuation">}</span></code></pre>
<ul>
<li><code>类组件</code></li>
</ul>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">class</span> <span class="token class-name">HelloWord</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>component</span><span class="token punctuation">{</span>
    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token punctuation">(</span><span class="token punctuation">{</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>Click</span> <span class="token punctuation">/></span></span>
        <span class="token punctuation">}</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span></code></pre>
<p><strong>函数式和类组件的区别？</strong></p>
<blockquote>
<p>函数式组件和类组件的区别和使用，函数式比较简单，一般用于静态没有交互事件内容的组件，类组件，一般为交互事件，进行数据的交互。</p>
</blockquote>
<ul>
<li><code>复核组件</code>  组建中又有组件</li>
</ul>
<h3 id="5-React-状态（State）-gt-Data"><a href="#5-React-状态（State）-gt-Data" class="headerlink" title="5. React 状态（State）=> Data"></a>5. React 状态（State）=&gt; Data</h3><blockquote>
<p>相当于 Vue 的 Data,但是 不建议主动赋值 而是采用 setState({ })</p>
</blockquote>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">Clock</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span>
        <span class="token comment" spellcheck="true">// 构造函数初始化，将需要改变的数据尽量放到 State 数据中。</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
            time <span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Date</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">toLocaleTimeString</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>

    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>当前时间：<span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>time<span class="token punctuation">}</span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
    <span class="token comment" spellcheck="true">// 声明周期函数</span>
    <span class="token comment" spellcheck="true">// 主键渲染完成挂载</span>
    <span class="token function">componentDidMount</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token function">setInterval</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">></span> <span class="token punctuation">{</span>
            <span class="token comment" spellcheck="true">// 此时不像 vue 一样 自动渲染</span>
            <span class="token comment" spellcheck="true">// error => this.state.time = new Date().toLocaleTimeString;</span>
            <span class="token comment" spellcheck="true">// 切勿直接修改 state 数据</span>
            <span class="token comment" spellcheck="true">// 和小程序 相似</span>
            <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
                time <span class="token punctuation">:</span> <span class="token keyword">new</span> <span class="token class-name">Date</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">toLocaleTimeString</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">}</span><span class="token punctuation">)</span>
        <span class="token punctuation">}</span><span class="token punctuation">,</span><span class="token number">1000</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span></code></pre>
<p>实例1： 点击内容进行切换</p>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">Clock</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>
    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
            c1 <span class="token punctuation">:</span> <span class="token string">""</span><span class="token punctuation">,</span>
            c2 <span class="token punctuation">:</span> <span class="token string">""</span><span class="token punctuation">,</span>
        <span class="token punctuation">}</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>clickEvent <span class="token operator">=</span><span class="token keyword">this</span><span class="token punctuation">.</span>clickEvent<span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span> 
    <span class="token punctuation">}</span>
    <span class="token function">clickEvent</span><span class="token punctuation">(</span>event<span class="token punctuation">)</span><span class="token punctuation">{</span>

        console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>event<span class="token punctuation">.</span>target<span class="token punctuation">.</span>dataset<span class="token punctuation">.</span>index<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">let</span> index <span class="token operator">=</span> event<span class="token punctuation">.</span>target<span class="token punctuation">.</span>dataset<span class="token punctuation">.</span>index<span class="token punctuation">;</span>
        <span class="token comment" spellcheck="true">// 这里 this 是 undefine</span>
        console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span>
        <span class="token keyword">if</span><span class="token punctuation">(</span> <span class="token number">1</span> <span class="token operator">==</span> index<span class="token punctuation">)</span><span class="token punctuation">{</span>
            <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
                c1 <span class="token punctuation">:</span> <span class="token string">"content active"</span><span class="token punctuation">,</span>
                c2 <span class="token punctuation">:</span> <span class="token string">"content"</span><span class="token punctuation">,</span>
            <span class="token punctuation">}</span><span class="token punctuation">)</span>
        <span class="token punctuation">}</span><span class="token keyword">else</span><span class="token punctuation">{</span>
            <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
                c1 <span class="token punctuation">:</span> <span class="token string">"content"</span><span class="token punctuation">,</span>
                c2 <span class="token punctuation">:</span> <span class="token string">"content active"</span><span class="token punctuation">,</span>
            <span class="token punctuation">}</span><span class="token punctuation">)</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>

    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>button</span> <span class="token attr-name">data-index</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>1<span class="token punctuation">"</span></span> <span class="token attr-name">onClick</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>clickEvent<span class="token punctuation">}</span></span><span class="token punctuation">></span></span>点击一<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>button</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>button</span> <span class="token attr-name">data-index</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>2<span class="token punctuation">"</span></span> <span class="token attr-name">onClick</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>clickEvent<span class="token punctuation">}</span></span><span class="token punctuation">></span></span>点击二<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>button</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span> <span class="token attr-name">className</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>c1<span class="token punctuation">}</span></span> <span class="token punctuation">></span></span> 内容一 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span> <span class="token attr-name">className</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>c2<span class="token punctuation">}</span></span> <span class="token punctuation">></span></span> 内容二 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>

<span class="token punctuation">}</span></code></pre>
<h3 id="6-React-父子组件传递数据-（Props）"><a href="#6-React-父子组件传递数据-（Props）" class="headerlink" title="6. React 父子组件传递数据 （Props）"></a>6. React 父子组件传递数据 （Props）</h3><p>父传统给子组件数据，单向流动，不能子传递给父</p>
<p><code>Props</code>的传值 可以为 <code>任意类型</code> 包括 函数。可以传递给父元素的函数，就可以修改父组件的数据。</p>
<p>实例1： 父组件 -&gt; 子组件的数据传递</p>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">ParentCom</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>

    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
            isActive <span class="token punctuation">:</span> <span class="token boolean">true</span>
        <span class="token punctuation">}</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>changeActive <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>changeActive<span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>button</span> <span class="token attr-name">onClick</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>changeActive<span class="token punctuation">}</span></span><span class="token punctuation">></span></span>控制子元素的显示<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>button</span><span class="token punctuation">></span></span>
                <span class="token operator">&lt;</span>ChildCom isActive <span class="token operator">=</span> <span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>isActive<span class="token punctuation">}</span> <span class="token operator">/</span><span class="token operator">></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>

    <span class="token function">changeActive</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
            isActive <span class="token punctuation">:</span> <span class="token operator">!</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>isActive
        <span class="token punctuation">}</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>

<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">ChildCom</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span><span class="token punctuation">{</span>

    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span>
    <span class="token punctuation">}</span>

    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">let</span> strClass <span class="token operator">=</span> <span class="token string">''</span><span class="token punctuation">;</span>
        <span class="token keyword">if</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span>isActive<span class="token punctuation">)</span><span class="token punctuation">{</span>
            strClass <span class="token operator">=</span> <span class="token string">'active'</span>
        <span class="token punctuation">}</span>
        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span> <span class="token attr-name">className</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token string">"content "</span><span class="token operator">+</span>strClass<span class="token punctuation">}</span></span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>我是子组件<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span></code></pre>
<p>实例2： 子组件 -&gt; 父组件 的数据传递</p>
<blockquote>
<p>这里不像 Vue 这么强大了，调用父元素的 函数 来改变父的状态</p>
</blockquote>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">ParentCom</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>

    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
            childData <span class="token punctuation">:</span> <span class="token string">''</span>
        <span class="token punctuation">}</span>

    <span class="token punctuation">}</span>

    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>子元素传递给父元素的数据 ： <span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>childData<span class="token punctuation">}</span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>ChildCom</span> <span class="token attr-name">setChildData</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>setChildData<span class="token punctuation">}</span></span> <span class="token punctuation">/></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>

    setChildData <span class="token operator">=</span> <span class="token punctuation">(</span>data<span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">></span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span><span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
            childData <span class="token punctuation">:</span> data<span class="token punctuation">,</span>
        <span class="token punctuation">}</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>


<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">ChildCom</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span><span class="token punctuation">{</span>

    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
            msg <span class="token punctuation">:</span> <span class="token string">'我是子消息'</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>

    <span class="token comment" spellcheck="true">// => 函数就不需要 .bind(this)</span>
    sendData <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">></span> <span class="token punctuation">{</span>
        console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span><span class="token function">setChildData</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>button</span> <span class="token attr-name">onClick</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">=</span><span class="token operator">></span> <span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>props<span class="token punctuation">.</span><span class="token function">setChildData</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span class="token punctuation">}</span></span> <span class="token punctuation">></span></span> 传递给父元素<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>button</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span></code></pre>
<h3 id="7-React-事件"><a href="#7-React-事件" class="headerlink" title="7. React 事件"></a>7. React 事件</h3><ol>
<li><p>它的事件是以<code>小驼峰命名法</code></p>
</li>
<li><p>onClick={ } </p>
<blockquote>
<p>React 入参是 对象的时候，它只是代理原生的事件对象，如果想要查看某一属性的值，必须属于完整属性</p>
</blockquote>
</li>
<li><p>阻止默认的 Form 的提交 , 阻止默认 <code>e.preventDefault();</code></p>
</li>
</ol>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">ParentCom</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span> <span class="token punctuation">{</span>

   <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">{</span>
       <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span> 
   <span class="token punctuation">}</span>

   <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{</span>
       <span class="token keyword">return</span> <span class="token punctuation">(</span>
           <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>form</span> <span class="token attr-name">action</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>http://www.baidu.com<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
               <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                   <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>button</span> <span class="token attr-name">onClick</span><span class="token script language-javascript"><span class="token punctuation">=</span><span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>parentEvent<span class="token punctuation">}</span></span><span class="token punctuation">></span></span>点击<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>button</span><span class="token punctuation">></span></span>
               <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
           <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>form</span><span class="token punctuation">></span></span>
       <span class="token punctuation">)</span>
   <span class="token punctuation">}</span>
   parentEvent <span class="token operator">=</span> <span class="token punctuation">(</span>e<span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">></span> <span class="token punctuation">{</span>
       console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>e<span class="token punctuation">)</span><span class="token punctuation">;</span>
       <span class="token comment" spellcheck="true">// 组织跳转到 百度</span>
       e<span class="token punctuation">.</span><span class="token function">preventDefault</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
   <span class="token punctuation">}</span>

<span class="token punctuation">}</span></code></pre>
<h3 id="8-React-条件渲染"><a href="#8-React-条件渲染" class="headerlink" title="8. React 条件渲染"></a>8. React 条件渲染</h3><p><code>实例1：</code>条件渲染是否 登录</p>
<pre class=" language-jsx"><code class="language-jsx"><span class="token keyword">import</span> React <span class="token keyword">from</span> <span class="token string">"react"</span><span class="token punctuation">;</span>
<span class="token keyword">function</span> <span class="token function">UserGreet</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token punctuation">(</span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>您已经登录<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>

<span class="token keyword">function</span> <span class="token function">UserLogin</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token punctuation">(</span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>请先登录<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>

<span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">class</span> <span class="token class-name">Apps</span> <span class="token keyword">extends</span> <span class="token class-name">React<span class="token punctuation">.</span>Component</span><span class="token punctuation">{</span>
    <span class="token function">constructor</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">super</span><span class="token punctuation">(</span>props<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>state <span class="token operator">=</span> <span class="token punctuation">{</span>
            isLogin <span class="token punctuation">:</span> <span class="token boolean">false</span>
        <span class="token punctuation">}</span>
    <span class="token punctuation">}</span>
    <span class="token function">render</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

        <span class="token keyword">let</span> element <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>

        <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>isLogin<span class="token punctuation">)</span><span class="token punctuation">{</span>
            element <span class="token operator">=</span>  <span class="token punctuation">(</span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>UserGreet</span> <span class="token punctuation">/></span></span><span class="token punctuation">)</span>
        <span class="token punctuation">}</span><span class="token keyword">else</span><span class="token punctuation">{</span>
            element <span class="token operator">=</span>  <span class="token punctuation">(</span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>UserLogin</span> <span class="token punctuation">/></span></span><span class="token punctuation">)</span>
        <span class="token punctuation">}</span>

        <span class="token keyword">return</span> <span class="token punctuation">(</span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span> 这是头部 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
                    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>第一种<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
                        <span class="token punctuation">{</span>element<span class="token punctuation">}</span>
                    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>

                    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>div</span><span class="token punctuation">></span></span>
                        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span>第二种<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
                        <span class="token punctuation">{</span><span class="token keyword">this</span><span class="token punctuation">.</span>state<span class="token punctuation">.</span>isLogin <span class="token operator">?</span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>UserGreet</span><span class="token punctuation">/></span></span> <span class="token punctuation">:</span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>UserLogin</span><span class="token punctuation">/></span></span><span class="token punctuation">}</span>
                    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>h1</span><span class="token punctuation">></span></span> 这是尾部 <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>h1</span><span class="token punctuation">></span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>div</span><span class="token punctuation">></span></span>
        <span class="token punctuation">)</span>
    <span class="token punctuation">}</span>

<span class="token punctuation">}</span></code></pre>
<p><code>实例2</code> 列表的渲染</p>
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